Thermostatic mixer valves for showers on boats....single lever or bar mixer type

[Roy Batty]

Having had great advice on removing my old calorifier and installing a new one I now find myself with a new dilemma.

 

My water is so hot that I need a mixer unit on the shower so that an unsuspecting guest doesn't scald themselves.

 

I know that some calorifiers have mixer valves on their outlet but mine doesn't so I need to mix the water as it hits the shower hose.

 

I have 15mm copper pipes and their centres are 95mm on an old fashioned twin tap shower unit. I would preferably like to keep the pipes at the same distance apart to avoid drilling new holes and moving pipework.

 

Does anyone have any suggestions of a single lever or bar mixer type that would fit to my existing spec?

 

As always, thank you for giving me the time of day with your advice.

 

All the best

 

Roy

[PeteS]

I had the same problem and changed mine for one similar to this

 

http://www.diy.com/nav/rooms/bathrooms/showering/showers/mixer-showers/Chrome-Bar-Mixer-Shower-11207505

[alan_fincher]

Or you can have a mixer valve on the calorifier outlet that limits the maximum temperature of ALL your supplied hot water, which would additionally make the hot taps at sinks and basins safer.

[Scholar Gypsy]

Or you can have (as I do)

 

• a mixer valve that mixes (very) hot and cold water to produce warm water for the shower and the washbasin - I have it set at a safe shower temperature
  
• very hot water fed to the galley hot tap, for washing up (and filling kettles)

Note that these mixer valves should have a one-way valve inside them, so you need to add a drain point downstream of them if you drain your water system in the winter.

[Bobbybass]

I had the same problem and changed mine for one similar to this

 

http://www.diy.com/nav/rooms/bathrooms/showering/showers/mixer-showers/Chrome-Bar-Mixer-Shower-11207505

 

I have one like this as I like the option of setting the temperature at the shower itself.

My wife is a lot shorter than I am and has the water quite hot as it falls and cools.

This is always the case wherever we are..she has it hotter.

I am tall and have the water cooler.

I did try a tank outlet mixer valve as it sounded sensible to limit the temperature at the taps, but I didn't like it as sometimes I 'fancied' the water a little hotter. I like to run hot water and then cold to cool it a little.

 

Personal preference comes in here.

[PeteS]

I looked at fitting a thermostatic mixing valve on the calorifier outlet but I was concerned about Legionnaires disease as the water must be higher than 40C to kill it

[Bobbybass]

I looked at fitting a thermostatic mixing valve on the calorifier outlet but I was concerned about Legionnaires disease as the water must be higher than 40C to kill it

Shoot it..just get a gun and shoot it....

Damn those Legionnaires !

[Biggles]

I have a standard domestic bar show mixer which is thermostatic a mixer set under the sink for the washing machine set at 40c so the machine has a warm water fill but not above the minimum wash temperature for a No. 4 wash then the bathroom basin and the kitchen sink are both as hot as the water in in the calorifier with a warning to guests.

[Chalky]

Or you can have a mixer valve on the calorifier outlet that limits the maximum temperature of ALL your supplied hot water, which would additionally make the hot taps at sinks and basins safer.

 

That's soft of what we did. I plumbed from the calorifier to the shower mixer in copper - the same copper pipe feeds a mixer that limits the temperature and feeds this to the other hot water taps. The main reason was that the water in the calorifier can get hotter that the plastic pipe is rated for.

[Grace and Favour]

Grohe (linky) are pricy - though their stuff is excellent quality (at least - the one we bought from them is!)

[Hawkmoth]

I had the same problem and changed mine for one similar to this

 

http://www.diy.com/nav/rooms/bathrooms/showering/showers/mixer-showers/Chrome-Bar-Mixer-Shower-11207505

We have exactly the same one on our boat, it works perfectly.

There is some leeway on the fitting centres, but if you have to drill holes then so be it. Or you could bring the pipework out a bit and then adjust it to the correct centres.

Bob

[smileypete]

Having had great advice on removing my old calorifier and installing a new one I now find myself with a new dilemma.

 

My water is so hot that I need a mixer unit on the shower so that an unsuspecting guest doesn't scald themselves.

 

I know that some calorifiers have mixer valves on their outlet but mine doesn't so I need to mix the water as it hits the shower hose.

 

I have 15mm copper pipes and their centres are 95mm on an old fashioned twin tap shower unit. I would preferably like to keep the pipes at the same distance apart to avoid drilling new holes and moving pipework.

 

Does anyone have any suggestions of a single lever or bar mixer type that would fit to my existing spec?

 

As always, thank you for giving me the time of day with your advice.

 

All the best

 

Roy

As others say the bar mixers usually come with 'dog leg' adapters but might not reach 95mm, though some are pretty near, maybe just enlarge the holes a little one way and fill with grout/sealant?:

 

http://www.ebay.co.uk/itm/Bristan-ORTA-Exposed-ADJUSTABLE-Bar-Mixer-Shower-Surface-Mounted-EVO-Kit-/160732533544

 

Failing that a TMV valve could be fitted in the hot feed close to the shower, set to say 43°C so the shower temp could be mixed down from there, loads on Ebay:

 

http://www.ebay.co.uk/sch/i.html?_sacat=0&_from=R40&_nkw=TMV+valve&_sop=15

 

cheers, Pete.

~smpt~

Edited June 21, 2013 by smileypete

[Keeping Up]

We have one mixer on the output from the calorifer, which brings the water down to a safe but uncomfortably hot temperature, which is fed to the kitchen tap (for washing up) and to the shower mixer. There is then another mixer under the washbasin, set to a lower temperature which allows you to wash your hands directly under the hot tap.

 

When I first connected it all up, with just the one mixer at the calorifier output, it wouldn't deliver any hot water at all when the engine had been running for a while. I eventually discovered that the mixer had a "safety" cut-out that shut down the hot supply if its input temperature exceeded 80 C. So I relegated that to under the washbasin and bought a different one for the calorifier output, one which didn't have the "safety" feature. That is how I ended up with the dual system, which I find works very well.

[bag 'o' bones]

It likely that the distances between the pipes will be standard therefore any shower should fit without having to adjust the pipes (cranked connectors are available if they are not)

 

On the subject of thermostatic valves look for an anti scold accredited model.

 

TVM2 is suitable for household use and TVM3 is the highest quality as used in hospitals and nursing homes.

 

Maintaining your calorifier at engine temperature means that you will be able to take a longer shower!

[Keeping Up]

It likely that the distances between the pipes will be standard therefore any shower should fit without having to adjust the pipes (cranked connectors are available if they are not)

 

On the subject of thermostatic valves look for an anti scold accredited model.

 

TVM2 is suitable for household use and TVM3 is the highest quality as used in hospitals and nursing homes.

 

Maintaining your calorifier at engine temperature means that you will be able to take a longer shower!

 

No the anti-scald accredited models will not work directly off water from the calorifier. That was the problem I had; they shut the hot supply down completely if the water gets above 80 (or sometimes 85) degrees C

[blackrose]

Or you can have a mixer valve on the calorifier outlet that limits the maximum temperature of ALL your supplied hot water, which would additionally make the hot taps at sinks and basins safer.

 

That's what I did.

 

I had to install a Y strainer on the hot water inlet of the TMV because I was in a hard water area and limescale from the calorifier kept clogging it up. Since then no problems.

I looked at fitting a thermostatic mixing valve on the calorifier outlet but I was concerned about Legionnaires disease as the water must be higher than 40C to kill it

 

I thought it was 60C, but anyway, how do you ensure that your hot water never falls below 40C (if you're not on shore power)?

 

Once you use some hot water from the calorifier your pump introduces cold water to the tank, cooling the water.

 

As long as the TMV is set above the temperature to kill Legionnaires that's all you can do. Although I understand your concerns, fitting a TMV to each outlet (or not fitting a TMV at all) doesn't solve the problem and is no safer because you can't guarantee that the water in your system will never fall below the desired temperature - unless you stay on shore power with an immersion heater on, or run your engine, etc. everyday. They're the only failsafe methods.

Edited June 21, 2013 by blackrose

[bag 'o' bones]

 

No the anti-scald accredited models will not work directly off water from the calorifier. That was the problem I had; they shut the hot supply down completely if the water gets above 80 (or sometimes 85) degrees C

Not sure I get what you mean. The TMV will only shut down the hot water if there not enough cold water present to maintain the outflow within the specified temperature range.

[Keeping Up]

Many mixers - particularly the ones that are certified as "anti-scald" such as the Caleffi range - include an additional safety device which shuts the whole thing down if the temperature of the incoming hot water exceeds 80 or 85 degrees. Since the water in the calorifier will often reach this temperature, such a mixer will be no use at all. It took me nearly 6 moths of frustration to track down the reason why my expensive Caleffi mixer wouldn't work if the engine had been running for an hour or more